Decorated wallboard and method of making the same



spots.

Patented Jane 1, E952 DECORATED WALLBOARD AND METHOD OF MAKING THE SAME Thomas P. Camp, Arlington Heights, 111., assignor to United States Gypsum Company, Chicago,

111., a corporation of Illinois No Drawing. Application March 1, 1946, Serial No. 651,381

9 Claims. (01. 15486) This invention relates to-sheets or boards having a protected decorative surface, and also relates to methods of producing said boards or sheets. It relates particularly to decorated wallboards having a cementitious core.

Wall boards having a surface of decorative value have been produced for a number of years. These, principally, were made in patterns simulating wood and are sometimes known as grain Two general methods of manufacture have been employed. The first method of applying a decorative surface was to adhere to the regular paper surface of the dry gypsum or other board a sheet of paper bearing the desired pat tern protected by a water and oil resistant film of lacquer. This sheet was applied to the gypsum board, for example, after it had been formed, dried and cut into sheets. This was an expensive procedure due to the extra handling of the boards, extra breakage, the cost of extra paper, etc.

The second method consisted of the application of a decorative pattern to the regular paper liner of the board before the board was formed, and then forming the board, cutting and drying it in the customary manner. This eliminated was not Water resistant. Furthermore it could not be varnished or otherwise finished without preliminary protective measures, either after drying or before erection of the board.

through the drying kiln, does not take varnish or stain properly since the varnish, etc., strikes through or penetrates the surface, forming "oil of the two surfaces of the board frequently results in warping during the drying operation, thus causing serious difficulty in the kiln.

An object of the invention, therefore, is to provide a decorated sheet or board having a protected surface suitable for washing.

It has been found that certain plasticized protein solutions and emulsions containing them in dercoater, will nevertheless permit the passage of moisture or steam therethrough during the drying of the boards.

Normally, a person skilled in the art of making gypsum wall board would expect that the application of a coating to one surface of a wet faces of the wet plasterboard in the kiln, but

also gave a vastly improved product.

As an illustration, but not as a limitation .of the principles of this invention the methodof placing a decorative woodgrain appearance upon one of the paper surfaces of a gypsum wallboard will be described in detail. Gypsum wallboard. stated succinctly, consists of a core containing rehydrated calcined gypsum with additives and having flrmly attached thereto on each side a layer of heavy paper known at times as a liner. It is not, however, tion of alone as it can of board having one or more liners and a wet core.

e liner consists of several plies or sheets multi-cylinder paper making ma- Generally the outermost plies are formed that the liner possesses wallboard chine. from a stronger fiber so adequate strength. In addition, one of the outer plies may consist of manila stock to provide a surface suitable for decoration. The paper to be used may also be supplied by the paper mill with the final or finish liner colored to a suitable shade for the type of wood graining which is to be applied upon it. For example, if the finished surface is to be a birch-like effect it will be light in color; if it is to be a walnut, it will be darker in color.

After the paper has been formed and dried it is ready for the application of the woodgrained effect. This can be accomplished in a number of ways well known to the art. One method is to print the grained effect on the paper using a roll or rolls, the surface or surfaces of which contain the impression of the graining effect it is desirable to produce. The appropriate color of ink limit this invention to this pattern or color for obviously any pattern or color may be printed or otherwise transferred to the surface to be decorated.

When the decoration has become sufficiently dry to permit handling, a coating of a special film forming material is applied and permitted to dry. When dry this material is quite resistant to moisture penetration.

After the sizing has been thoroughly dried, the paper is wound into rolls, whence it is transported to the board forming machine and made into a. board in the regular manner. This process consists of forming a bottom and top layer of paper so as to enclose a plaster core containing calcined gypsum and water by means of master rolls. The board, after the gypsum core has set up, is cut into the lengths desired and then drying kiln. The kiln may be burner, from high pressure slight adjustment may have kiln conditions in order to properly dry the new material. These adiustments can readily be made by those familiar with the manufacture of wallboard.

The appearance of the product formed by this improved process will be found to be as good or better than that formed by the method now being used. The decorative surface of the board will be superior in its ability to take a. varnish and there will be no danger of a separation of the grained surface from the base paper. In addition, the cost and difficulty of manufacture will be greatly reduced.

It has been found that a in an aqueous solution may be used as a basis for the special protective film. Casein, vegetable protein, glue, blood, albumen, etc. are some that can be readily used. They may be combined with number of materials intended to limit the applicafactory for the purpose entire portion of the plasticizers such as urea, dicyandiamide and ethyl carbamid together with insolubllizing agents or tanning agents such as hexamethylenetetramine, formaldehyde, alum, chrome tanning agents. Likewise these water solutions may be converted into an emulsion with various oil type varnishes, oil modified alkyd resins, etc. When this is done, it is important that the solutions be in the continuous phase and the other ingredients in the discontinuous phase.

An example of a clear coating which is satisintended is as follows:

A casein paste is made according to the following formula:

Lbs. Casein 220 Water 600 The casein is soaked in the water for about 25 minutes at room temperature and to this is slowly added 60 lbs. of borax dissolved in 420 lbs. of hot water. This mixture is cooked for 30 minutes at F. and is then cooled and ready for use. The coating applied to the paper is made by mixing together the following ingredients:

10 gallons above casein solution 6 lbs. urea .6 lbs hexamethylenetetramine 2 /2-3V gal. water The urea and hexamethylenetetramine are dissolved in the water and then slowly stirred into the casein solution. It is important that the stirring be complete in order to prevent the formation of lumps. 1

The above quoted equivalent materials of course cannot be substituted directly in this formula, but must be used with the proper solvent and in the proper amount as determined by the nature of the paper and the equipment used for applying the solution;

As a further illustration which is not to be construed as a limitation of the principles underlying this invention, it is possible to use oil modified alkyd resins in an emulsion form. For instance to the above casein solution, may beadded the following reacted alkyd resin mixture:

- Percent Soya bean oil fatty acids 50 Phthalic anhydride 40 Glycerol '10 The alkyd resin is emulsified with the aid of ammonia or some other volatile alkali and then stabilized with a casein solution. The amount of casein is approximately 10% of the dry weight solids. The alkyd emulsion generally contains about 50% by weight of solids.

It will readily occur to those familiar with the art of forming a wallboard having a decorative surface that many modifications can be made in the details of procedure process and still be within the scope of this invention. For example, it is possible to have the enclosin paper liner which is the base for the decoration, colored to the shade advisable for the particular effect desired instead of the top liner alone as suggested. Also it may only be necessary to apply this base color as a stain to the paper surface before application of the decoration. It is possible to apply a sizing layer between the base color and the to the paper before applying The coating, if desired, may be .It also is the base stain. pigmented to produce a solid color.

in carrying out this obvious that the coating may be applied in any of the well known ways. It may be advisable to a1 1y a surfacing material over the top sizing coat after drying and still not digress from the essence of this invention which is the formation of a decorated surface directly upon an enclosing paper liner of a wallboard in such a way that water or water vapor may pass therethrough during drying but which when cooled will be water resistant and suitable for the application of varnish or other decorative material in the field without discoloration of the surface.

Though the above illustrates but one of the many modifications, extensions, adaptations and variations possible, it is not intended to be limited to the same, since it is possible to be still within the spirit and scope of the principles of this invention as defined in the hereunto appended claims.

I claim:

1. The method of producing decorated gypsum board, which comprises applying a decorative pattern and a protein base coating material to a surface of a sheet of paper, drying said coated and decorated sheet, applying said dried decorated and coated paper to one surface of a plastic slurry of ypsum base core material having a substantial proportion of water, forming a laminated board therefrom and subjecting said board to an elevated drying temperature so as to expel at least part of said water from said board as vapor through said coated and decorated surface.

2. The method of producing a decorated surface gypsum board, which comprises applying a protein coated paper sheet to the wet gypsum board, the said protein selected from the group of casein, soya bean, peanut and zein, and subjecting said board to an elevated drying temperature to expel water as vapor through said sized and decorated surface without formation of blisters and peelers.

3. The method of producing a decorated gypsum board, which comprises applying the reaction product of casein and borax cooked at 170 F. for thirty minutes to a decorated sheet of 6 5. In the process of producing a decorative surface on a gypsum wallboard, the steps of placing a moistened cementitious core plastic mix on the uncoated side of an inverted sheet whose surface is decoratively coated, said coating comprising a protein emulsified alkyd resin and a pigment, placing on said moistened cementitious core plastic mix a cover sheet, and simultaneously pressing the said lamination to desired thickness, hardening the said moistened cementitious plastic mix by allowing it to stiffen and set without disturbance to a hard wet core in the lamination, cutting the said hardened lamination to desired size, inverting the cut lamination to expose the coated surface and drying said cut lamination in a kiln at a temperature sufiiciently high to remove excess of said moisture from said core and said coating emulsion, whereby when the said laminated wallboard is dry a washable and decorative surface is obtained on said wallboard.

6. A gypsum wallboard comprising a cementitious core and covering sheets, at least one of said covering sheets coated with the reaction product of a protein solution cooked at a temperature of not less than 170 F. and not more than 210 F. for a time of not less than twenty minutes; the said coated liner characterized by its ability to resist penetration of oil and varnish stains and also provide a washable and cleanable surface.

7. In the product of claim 6, wherein the said protein is selected from the group consisting of casein, albumen, soya bean, peanut and zein.

8. In the product of claim 6, wherein the said protein is fiexibilized with a reagent selected from the group of urea, glycerine, dicyandiamide, and ethyl carbamid.

9. In the product of claim 6, wherein the said protein is water insolubilized with a reagent vapor pervious flexible material, drying the said coated sheet, applying said sheet to a moist gypsum board, and subjecting said board to an elevated drying temperature to cause water vapor to be expelled from said board through said sheet.

4. The method of producing a decorated gypsum board, which comprises applying a pigmented coating solution of casein, an alkali and sheet, applying said sheet to a moist gypsum board, and subjecting said board to an elevatgd drying temperature to cause water vapor to e expelled from said board through said sheet.

, tetramine,

selected from the group of hexamethyleneformaldehyde, alum, soluble chromates of alkali metals and ammonium.

THOMAS P. CAMP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Robertson et al. Sept. 23, 1947 

1. THE METHOD OF PRODUCING DECORATED GYPSUM BOARD, WHICH COMPRISES APPLYING A DECORATIVE PATTERN AND A PROTEIN BASE COATING MATERIAL TO A SURFACE OF A SHEET OF PAPER, DRYING SAID COATED AND DECORATED SHEET, APPLYING SAID DRIED DECOPERATMOSPHERIC PRESSURE AND IN THE PRESENCE OF A HYDROCARBON SOLUBLE PEROXIDE CATALYST FOR A PERIOD SUFFICIENT TO CONVERT NOT MORE THAN 80% OF THE DIOLEFIN INTO A LINEAR OILY POLYMER AND NOT MORE THAN 5% INTO A DIOLEFIN DIMER, THE METHOD OF REDUCING THE FORMATION OF SOLID INSOLUBLE POLYMER WHICH COMPRISES CONTINUALLY FLUSHING THE 